Tea leaf, in the main (6)
I believe the answer is:
pirate
'the main' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'tea leaf' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'tea' is 'ate' which is present in the answer.
'leaf' could be 'p' and 'p' is located in the answer.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for pirate that I've seen before include "sailor" , "Hook for one" , "Criminal on the high seas" , "Robber on the high seas" , "Robber on the high scas" .)